border-block-start: 1px; border-block-start: 2px dotted; border-block-start: medium dashed blue;  /* Global values */ border-block-start: inherit; border-block-start: initial; border-block-start: revert; border-block-start: unset; 

border-block-start

The border-block-start CSS property is a shorthand property for setting the individual logical block-start border property values in a single place in the style sheet.

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

border-block-start: 1px; border-block-start: 2px dotted; border-block-start: medium dashed blue;  /* Global values */ border-block-start: inherit; border-block-start: initial; border-block-start: revert; border-block-start: unset; 

border-block-start can be used to set the values for one or more of border-block-start-width, border-block-start-style, and border-block-start-color. The physical border to which it maps depends on the element's writing mode, directionality, and text orientation. It corresponds to the border-top, border-right, border-bottom, or border-left property depending on the values defined for writing-mode, direction, and text-orientation.

Related properties are border-block-end, border-inline-start, and border-inline-end, which define the other borders of the element.

Values

The border-block-start is specified with one or more of the following, in any order:

The width of the border. See border-width.

The line style of the border. See border-style.

The color of the border. See color.

Formal definition

Formal syntax

<'border-top-width'> || <'border-top-style'> || <color>
where <color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hwb()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
where <rgb()> = rgb( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? ) | rgb( <percentage>#{3} , <alpha-value>? ) | rgb( <number>#{3} , <alpha-value>? )<rgba()> = rgba( <percentage>{3} [ / <alpha-value> ]? ) | rgba( <number>{3} [ / <alpha-value> ]? ) | rgba( <percentage>#{3} , <alpha-value>? ) | rgba( <number>#{3} , <alpha-value>? )<hsl()> = hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsl( <hue>, <percentage>, <percentage>, <alpha-value>? )<hsla()> = hsla( <hue> <percentage> <percentage> [ / <alpha-value> ]? ) | hsla( <hue>, <percentage>, <percentage>, <alpha-value>? )<hwb()> = hwb( [<hue> | none] [<percentage> | none] [<percentage> | none] [ / [<alpha-value> | none] ]? )
where <alpha-value> = <number> | <percentage><hue> = <number> | <angle>

Examples

Border with vertical text

<div>   <p class="exampleText">Example text</p> </div> 

div {   background-color: yellow;   width: 120px;   height: 120px; }  .exampleText {   writing-mode: vertical-rl;   border-block-start: 5px dashed blue; } 

Specifications

See also

Last modified: Aug 12, 2021, by MDN contributors